A plane plate for a pressing tool of a press; wherein the plane plate for activating a punch of the press by way of at least one lifting cylinder is displaceable along an axial direction; wherein the plane plate has a link to the at least one lifting cylinder, at least one cylindrical guiding face which for contacting a guide column is parallel with the axial direction, and a centrally disposed receptacle for contacting the punch or a punch holder of the press; wherein the plane plate in at least a first cross section which between the receptacle and the guiding face runs parallel with the axial direction and along a radial direction that runs so as to be perpendicular to the axial direction has at least a first region in which a wall thickness of the plane plate is continuously variable.

A method for manufacturing a jewel of the polycrystalline type, in particular for a timepiece, the jewel including, for example, poly-ruby of the type al2O3Cr or Zirconia of the type ZrO2, the method including a first step of producing a precursor, and a second step of pressing the precursor in order to form a body, the pressing being carried out using a pressing device provided with an upper die and a lower die defining a pressing space in which the precursor is disposed, the device being provided with a wire passing through at least part of the lower die to open out into the pressing space, the lower die being capable of sliding about the wire, the pressing taking place by bringing the lower die and the upper die closer to one another to form a body comprising a bottom face provided with a hole.

A method for manufacturing a jewel for a timepiece, the jewel including, for example, poly-ruby of the Al2O3Cr type or Zirconia of the ZrO2 type, including first producing a precursor and a then pressing the precursor in order to form a body, the pressing being carried out using a pressing device provided with an upper die and a lower die defining a pressing space wherein the precursor is disposed, the upper die including a concave portion of oblong shape, the device having a wire at least partially traversing the lower die to open into the pressing space, the lower die being able to slide around the wire, the pressing being carried out by bringing the lower die and the upper die closer together to form a body including an upper face provided with a dome and a lower face provided with a hole extending at least partially into the dome.

A plane plate for a pressing tool of a press; wherein the plane plate for activating a punch of the press by way of at least one lifting cylinder is displaceable along an axial direction; wherein the plane plate has a link to the at least one lifting cylinder, at least one cylindrical guiding face which for contacting a guide column is parallel with the axial direction, and a centrally disposed receptacle for contacting the punch or a punch holder of the press; wherein the plane plate in at least a first cross section which between the receptacle and the guiding face runs parallel with the axial direction and along a radial direction that runs so as to be perpendicular to the axial direction has at least a first region in which a wall thickness of the plane plate is continuously variable.

Process for forming tiles which provides for pressing a building material in a cell of a mold of a press by means of an isostatic punch, in which the punch has a compaction surface that is elastically deformable and provided with projections in order to attain cavities on an internal face of a tile and with recesses in order to shape feet projecting on the internal face, in which such punch comprises means for feeding a pressurized fluid and a pressure compensation circuit shaped in order to form pockets of the aforesaid fluid at the recesses.